The Whitworth thread form (55° thread angle, a thread depth of 0.640327p, radius of 0.137329p, rounded roots and crests, and a set of standard pitches p) was designed in 01841; that's when screws started being made with specifically designed pitch and thread shape. The Unified Thread Standard used today is virtually identical to the Sellers thread from 01864, though the metric pitches were added later, and standardized internationally in 01898, and some problems in the UTS were ironed out in 01949 in the wake of wartime Whitworth/Sellers incompatibilities.
So I would say screw threads have only evolved very slightly over the last century. Screw heads evolved quite a lot during that time, though: Robertson heads are from 01907 (just outside the century!), Phillips got his patent in 01932, hex-key screws are from 01936, and then we have hex head, Pozidriv, Torx, external Torx, and literally dozens of others. Hex heads pretty much replaced square head screws sometime around 01960.
(Also, bolts replaced rivets for structural steel about 100 years ago, due to improvements in heat treatment that couldn't be applied to rivets.)
More interesting to me is the increasing number of snap-fit fasteners, which can often replace screws with greatly improved convenience at lower cost. These aren't always applicable, and sometimes they're designed badly (Ramagon and USB plugs come to mind) but when they're designed well they often have much longer life than screw fasteners. Also, they don't vibrate free the way screws do (without lockwire or loctite, anyway).
for other materials there has been more innovation later for threads, and for special uses of metal screws as well, for example self-tapping screws and coating of screws.
side question: why do you prefix years with a leading zero?
> CELO is leading the self-tapping and self-drilling screw market.
> CELO's self-tapping and self-drilling screws offer the widest selection for installations of joining metals, PVC profiles and aluminium sheets.
> In this section you will find our screws in all sizes, recesses, head types and coatings.
and then pages over pages of a catalogue.
it was the first catalogue link searching for "self taping and self drilling screws"
https://en.wikipedia.org/wiki/Screw_thread#History_of_standa...
So I would say screw threads have only evolved very slightly over the last century. Screw heads evolved quite a lot during that time, though: Robertson heads are from 01907 (just outside the century!), Phillips got his patent in 01932, hex-key screws are from 01936, and then we have hex head, Pozidriv, Torx, external Torx, and literally dozens of others. Hex heads pretty much replaced square head screws sometime around 01960.
(Also, bolts replaced rivets for structural steel about 100 years ago, due to improvements in heat treatment that couldn't be applied to rivets.)
More interesting to me is the increasing number of snap-fit fasteners, which can often replace screws with greatly improved convenience at lower cost. These aren't always applicable, and sometimes they're designed badly (Ramagon and USB plugs come to mind) but when they're designed well they often have much longer life than screw fasteners. Also, they don't vibrate free the way screws do (without lockwire or loctite, anyway).